The phrase "beast burden" implies a heavy load or responsibility that one must bear, often likened to the weight carried by a beast of burden. Antonyms for "beast burden" would therefore be words or phrases that suggest lightness, ease, or freedom. Some possible antonyms might include, "carefree," "effortless," "unencumbered," "unburdened," "liberated," or "unrestricted." These words evoke a sense of relief and release from the weight of responsibility and highlight the joy and ease of living without the burden of demanding obligations.